In order to understand the function of the sweet potato brassinolide (BR) response gene BES1 and its expression characteristics in different tissues, we used the sweet potato (Ipomoea batatas L.) genomic library to screen the wellpreserved BES1 gene sequence primers, and the genomic DNA of sweet potato variety ‘Guangshu 87’ was used as a template for PCR amplification. The sweet potato BES1 gene (GenBank accession number MH448304) was successfully cloned, and gene length is 2 256 bp, encoding 322 amino acids. Phylogenetic tree analysis showed that BES1 is closely related to that of tomato and sesame, and the amino acid sequence has a highly conserved Nterminal domain and PEST domain. qRTPCR analysis showed that the expression of BES1 gene was the highest in the growth stage of sweet potato, and it was induced by phytohormone brassinolide. The expression was the highest when the concentration of BR was 10 μmol/L. The results laid a foundation for further study of the function of sweet potato BES1 gene, and had certain reference value for genetic improvement of sweet potato and breeding of resistant varieties.